Removable cartridge for the inked ribbon for typewriters, calculating machines or other office machines

ABSTRACT

A removable cartridge for an inked ribbon for an office machine comprises a container rotatably supporting two ribbon-carrying spools. The container has a first side wall provided with a pair of slits for the passage of the inked ribbon from the one to the other of said spools. A pair of apertures in a second side wall opposite to said first side wall allows entry into said container of sensing elements of a ribbon reversal feed mechanism for sensing the amount of inked ribbon on said spools. The sensing elements cooperate with corresponding latch levers of a reversal member which, by means of a reversal spring actuates a feed element for driving the spools carrying said ribbon in one sense and the other sense respectively. A closure member of the machine is movable between a first position wherein the cartridge is held on the machine, and a second position wherein the sensing elements are withdrawn from said apertures.

United States Patent Garberi et a1.

1 1 REMOVABLE CARTRIDGE FOR THE INKED RIBBON FOR TYPEWRITERS,CALCULATING MACHINES OR OTHER OFFICE MACHINES [75] Inventors: SergioGarberi; Lorenzo Bertino,

both of lvrea. Italy {73] Assignee: Ing. C. Olivetti & C., S.p.A.,

IvrealTorino), Italy [22] Filed: Oct. 20, 1972 [21] Appl. No: 299,379

[30] Foreign Application Priority Data Dec. 6, 1972 Italy 70,460/71 Dec.30. 1972 Italy 68,360/72 [521 US. Cl 197/151; 197/161 (51] Int. Cl B41j33/14 [58] Field of Search ..197/151,160,161,l62,

[56] References Cited UNITED STATES PATENTS 111115.594 1/1912 Spurgin197/151 1,871,232 8/1932 Foster 197/151 UX 1,944.023 l/1934 Ford 197/151UX 2,825.450 3/1958 Lambert 197/151 X 2,902,136 9/1959 Whippo 19711653,349,887 10/1967 Goff 3,425,532 2/1969 Dannatt 197/151 June 17, 197511,513,957 5/1970 Ricciardi et al. 197/151 3,604.549 9/1971 Caudill eta1. 197/151 3,632.052 1/1972 Read 197/151 UX 3,643,779 2/1972 Andersonet a1. 197/151 Primary Examiner-Ernest T. Wright, Jr. Allorney, Agent,or FirmSchuyler, Birch, Swindler, McKie & Beckett [57] ABSTRACT Aremovable cartridge for an inked ribbon for an office machine comprisesa container rotatably supporting two ribbon-carrying spools. Thecontainer has a first side wall provided with a pair of slits for thepassage of the inked ribbon from the one to the other of said spools. Apair of apertures in a second side wall opposite to said first side wallallows entry into said container of sensing elements of a ribbonreversal feed mechanism for sensing the amount of inked ribbon on saidspools. The sensing elements cooperate with corresponding latch leversof a reversal member, by means of a reversal spring actuates a feedelement for driving the spools carrying said ribbon in one sense and theother sense respectively. A closure member of the machine is movablebetween a first position wherein the cartridge is held on the machine,and a second position wherein the sensing elements are withdrawn fromsaid apertures.

17 Claims, 8 Drawing Figures PATENTEDJUN17 I975 889.795

PATENTEDJUN 17 ms SHEET Fig.4

PATENTEDJUN 17 ms SHEET Fig.7

REMOVABLE CARTRIDGE FOR THE INKED RIBBON FOR TYPEWRITERS, CALCULATINGMACHINES OR OTHER OFFICE MACHINES BACKGROUND OF THE INVENTION Thepresent invention relates to a removable cartridge for the inked ribbonfor typewritters, calculating machines or other office machines.comprising a container and two ribbon-carrying spools rotatable thereinin either direction. the container having at least one main wall towhich the axes of both spools are perpen dicular. a series of side wallsperpendicular to the main wall and a pair of slits in one of the sidewalls for the passage of the inked ribbon from the one of the other ofthe spools along a path which, between the slits, lies outside thecontainer.

Cartridges for an inked ribbon are known which are provided with aclosed container. in which the ribboncarrying spools rotate in bothdirections under the action of a reversal mechanism. The reversalmechanism of the machine is provided with a pair of sensing elementsfulcrumed internally on the entrainment pins for the spools. Eachsensing element is thrust from the inside against the ribbon coils woundon to the spool, through an aperture in the pin and an aperture in thecore of the spool. The sensing elements then control the reversal of themovement of the ribbon. when the number of coils of wound ribbon on aspool is no longer sufficient to hold the sensing element in. The use ofsenser elements of this type, however. makes the reversal mechanism forthe ribbon rather complicated and costly to realise.

Also known are typewriters which are provided with a reversal mechanismfor the movement of the ribbon controlled by a sensor element whichrests from the outside on the ribbon coils of the feed spool or of thetake-up spool. The sensor element thus tests the quantity of woundribbon, ordering the reversal when this quantity is less than apre-established minimum number of coils, or else when it is greater thana maximum of coils which is likewise pre-established. This reversalmechanism is very simple and therefore economical, but requires, for thereplacement ofa used ribbon, that the sensor element be pulled away fromthe relative spool. so as to allow the spool to be pulled off its pin.It is therefore not possible to use ribbon-carrying cartridges of knowntype, which have closed containers that do not allow the use of sensorelements which test externally the quantity of ribbon wound on thespools.

SUMMARY OF THE INVENTION In accordance with the present invention, thereis provided a removable cartridge for the inked ribbon for an officemachine, comprising a container and two ribboncarrying spools rotatabletherein in either direction of rotation. the container having at leastone main wall to which the axes of both spools are perpendicular, aseries of side walls perpendicular to the main wall, a pair of slits inone of the side walls for the passage of the ribbon from the one to theother of the spools along a path which, between the slits. lies outsidethe con tainer, and a pair of apertures in a side wall opposite the saidone wall, each ofthe said apertures being associated with one of thespools and being adapted to allow entry into the container of sensingelements for sensing the amount of inked ribbon on the spools.

The invention further provides an office machine incorporating such acartridge, means releasably attaching the cartridge to the machine, anda ribbon reversal mechanism including two sensing elements which enterthe two apertures respectively and bear against the inked ribbon on thetwo spools respectively.

The closure member can comprise a closure member pivotally mounted onthe machine for movement between a first position in which it holds thecartridge on the machine and a second position in which the cartridge isfree to be taken off the machine. the closure member being arranged toact on the sensing elements through a coupling mechanism such that, whenthe clo sure member is in the second position, the sensing elements arewithdrawn from the apertures.

The cartridge in accordance with the invention is simple and economical.This cartridge allows use of a simple attaching means and a simplereversal mechanism for the movement of the ribbon which, in combinationwith the cartridge, realise an economical and reliable whole.

BRIEF DESCRIPTION OF THE DRAWING A preferred embodiment of the inventionis described by way of example in the following description withreference to the accompanying drawing, in which:

FIG. 1 is a partial plan view of a cartridge for the inked ribbonembodying the invention and of a detail of a calculating machine onwhich the cartridge is mounted;

FIG. 2 is a partial section in accordance with the line II-Il of FIG. 1:

FIG. 3 is a partial section in accordance with the line III-lll of FIG.1;

FIG. 4 is a partial plan view of the cartridge in a special position ofthe detail of FIG. 1;

FIG. 5 shows a partial plan view of the cartridge of FIG. 1 with anotherdetail of the calculating machine;

FIG. 6 shows a section in accordance with the line VI-VI of FIG. 5;

FIG. 7 shows a section in accordance with the line VIIVII of FIG. 6 ofsome details of FIG. 5;

FIG. 8 shows the details of FIG. 7 in a second operative position.

DESCRIPTION OF A PREFERRED EMBODIMENT With reference to FIG. I, thecartridge 6 for the inked ribbon 12 comprises a container 5 of plasticmaterial having a substantially parallelepipedal shape. The container 5is provided at the rear side arms, two arm 7 which embrace a cylindricalwriting head 8 of a calculating machine. The head 8 is movable betweenthe arms 7 from a position of rest indicated in a solid line to anend-of-line position indicated in chain-dotted lines, in order to writea line of print on a tally roll 9 (FIG. 2). An inked ribbon 12 (FIG. I)is tensioned between the ends of the arms 7 which are suitably shapedand inclined to present the ribbon l2 parallely to the line of print onthe tally roll 9 (FIG. 2) and at the right angle (FIG. 1) with respectto the ribbon l2 emerging from the container through two slits 11adjacent the arms 7.

The container 5 is closed at the top by a lid 17 and has. in the rearpart, a central recess which defines a space 13, which is connected to aspace 14 (FIG. 3) formed by a channellike depression in the lid I7. Thecontainer 5 (FIG, 1) is provided, in the front side, with a centralrecess which forms a space 21 and with two apertures 22 and 23 throughits front side wall. The container 5 also has central ribbing 24, inline with the spaces 13, 14 and 21, which divides it into two equalchambers. in which two spools 18 and 19 are rotatably mountedv Thespools 18 and 19 store the wound inked ribbon 12 and rotate in thecontainer 5 so as to convey the ribbon 12 from the one spool to theother over the arms 7 and through the slits 11. Each spool 18 and 19 hasthe shape of a cup turned upside down and is provided with a centralholc surrounded by a toothed crown 26 or 27 respectively.

The crowns 26, 27 have three teeth which are lodged in a hole 28 (FIG.3) or 29 respectively, formed in a lower portion 16 of the container 5.The hole 28 or 29 is defined by a sleeve 31 or 32 which protrudes insidethe container 5. On each sleeve 31, 32 there normally rests the base ofthe spool 18 or 19.

The container 5 has, on its walls 33 and on the central ribbing 24, lugs34 (FIG. 1) which engages in as many slots 36in the lid 17, in order tofix the lid 17 to the container 5. Internally the lid 17 hashemispherical pips 37 and 38 (FIG. 3) overlying the spools 18 or 19. Thepips 37, 38 are arranged at l one to the other and do not allow thespools 18, 19 to rise from the re spective sleeves 31, 32 during therotation for the advance of the inked ribbon 12.

Two revolving shafts 41 and 42 are mounted on a horizontal base 43 ofthe machine. The shafts 41 and 42 are connected to an advance andreversal device for the movement of the inked ribbon 12 contained insidethe base 43 and which will be described subsequently. These shafts 41and 42 are shaped at the top so as to have in their ends three incisionsin the form of an inverted pyramid 44 or 46 respectively (FIG. 1)capable of engaging with the teeth of the crowns 26 and 27 presented bythe spools l8 and 19 respectively.

Above the base 43 (FIGv 2) and fixed thereto there is arranged ahorizontal platform 47, on which rests the cartridge 6. Fixed on theplatform 47 there is a pin 48, about which there are fulcrumed twosensing elements 49 and 51 (FIG. 1) of the reversal mechanism for theinked ribbon 12. These sensing elements 49, 5] comprise a pair ofscissor levers 52 and 53 which, under the action of a spring 54,normally rest on the inked ribbon 12 wound on the spools 18 and 19, atthe same time keeping the coils tight on the spools 18 and 19. Thespring 54 is fixed with its ends in corresponding 19. The spring of thelevers S2 and 53 and is tensioned at its central portion round the pin48.

Fixed on the sensing elements 49 and 51 are corresponding pins 56 and57, which cooperate through slotted holes 58 and 59 in the platform 47with a latch lever 121 or 122 (FIG. 7) of the mechanism for control ofthe reversal of the movement of the inked ribbon 12 contained in thebase 43. Each sensing element 49, 51 (FIG. 1) has a tongue 61, 62respectively, with which a releasing device 63, 64 respectively cancooperate. The two releasing devices 63, 64 are fulorumed on theplatform 47 and each has a projection 66, 67 respectively, capable ofcooperating with a cam 68, 69 respectively. These cams 68 and 69 areconstituted by lugs projecting at the bottom and on the front side of aclosure plate 71 of an inverted *T shape.

The closure plate 71 is made of plastic material and is pivoted on twopins 72 on two tongues 73 of the platform 47. The closure plate 71 canthus be swung up to the open, broken line position of FIG. 2. In itsfront edge the closure plate 71 (FIG. 2) has a central projection 74, inwhich there is made a V" incision 75 capable of cooperating with a leafspring 76 integral with the platform 47, when the closure plate 71 isrotated by into the open position.

The closure plate 71 includes on the rear side a tongue 77, which islodged in the space 14 (FIG. 3) of the lid 17, and a lower projection 78keeps the cartridge 6 in contact with the platform 47.

The tongue 77 ends with a downwardly bent projec tion 79 (FIG. 2) in theform of a V which is lodged in the rear space 13 of the container 5. Theprojection 79 has, at the rear, a detent lug 81 capable of engaging witha shoulder 82 presented by a tongue 83 of the platform 47. Theprojection 79 has, furthermore, a rear ledge 84 substantially coplanarwith the tongue 77 by means of which, taking advantage of the elasticityof the material, and by exerting a slight manual pressure. one canengage or disengage the detent lug 81 from the shoulder 82. The space 13of the container 5 allows the tongue 83 to remain substantially alignedwith the rear wall of the container 5 (FIG. 1) and outside the zone ofrectilinear movement of the head 8.

To replace a used cartridge 6 by a new one, one acts in the followingmanner. With one hand one exerts a slight pressure on the ledge 84 (FIG.2) of the projection 79 in order to disengage the detent lug 81 from theshoulder 82 and then one swings up the closure plate 71. The cams 68(FIG. 1) and 69 bear against the respective projections 66 and 67 of thereleasing devices 63 and 64 respectively. causing these devices 63 and64 to rotate, the first device 63 in the clockwise direction and thesecond device 64 in the anticlockwise direction. Each releasing device63, 64 engages the tongue 61 and 62 of the respective sensing element49, 51. The two sensing elements 49, 51 rotate, the first sensingelement 49 in the anticlockwise direction and the second sensing element51 in the clockwise direction against the action of the spring 54.

After a rotation of about 90 of the closure plate 71, the leaf spring 76engages in the incision 75. The releasing devices 63 and 64 have rotatedthe levers 52 and S3 of the sensing elements 49 and 51 out of thecontainer 5, arranging them aligned in accordance with one and the sameplane parallel to the shafts 41 and 42 as shown in FIGv 4. The closureplate 71 is then in the vertical position and the sensing elements 49and 51 are disconnected from the cartridge 6, allowing the removal fromthe platform 47 of the cartridge 6.

The used cartridge 6 is then lifted off with one hand and is replaced byanother one by resting this latter on the platform 47 so as to bring thecrowns 26 and 27 (FIG. 1) into engagement with the shafts 41, 42. Onethen flaps down the closure plate 71 overcoming the resistance of theleaf spring 76.

The spring 54 causes the sensing elements 49 and 51 to rotate, the firstsensing element 49 in the clockwise direction and the second sensingelement 51 in the anticlockwise direction. The levers 52 and 53 passthrough the apertures 22 and 23 of the container 5 and rest on the coilsof inked ribbon 12 wound on the two spools l8 and 19. By now exerting aslight pressure downwards on the ledge 84 of the projection 79, thedetent lug 81 snaps under the shoulder 82 of the tongue 83 (FIG. 2). Thelower projection 78 of the tongue 77 is lodged in the space 14 (FIG. 3)of the lid 17 and keeps the cartridge 6 against the platform 47 throughthe elasticity of the tongue 77, and therefore in this way fixedremovably to the machine. The two releasing devices 63 and 64 (FIG. I)rotate loosely and remain inactive during the functioning of thereyersal mechanism for the inked ribbon 12.

During the change of the cartridge 6, the stretch of inked ribbon 12which projects out from the arms 7 is not in tension. because the spoolsl8 and 19 may have been rotated slightly in the clockwise oranticlockwise direction by the incisions 44 and 46 during the engagementwith the crowns 26 and 27. Nevertheless. no sooner does the writingcycle begin than the inked ribbon 12 is brought rapidly into tension.During the fenctioning the levers 52 and 53 exert a certain restrainingpressure on the coils of the inked ribbon 12.

With reference to FIG. 5, the reversal mechanism for the feed movementof the inked ribbon 12 comprises a series of flat gears 104, 106, I07.108, 109 and 111 always in mesh one with another. The gear 104 isintegral with a driving shaft 112 ofthe calculating machine, alwaysrevolving in the anticlockwise direction. The gears 106, 108 and 109 arerotary on axes 113 fixed below the platform 47 (FIG. 6). The gears 107and 111 are rotary on slee\ es 114, they too fixed at the bottom to theplatform 47. Two gears 116, 117, similar to the gears 111 and 107respectively. are in one piece with the shafts 41 and 42 respectively,which are rotatable in the sleeves [14. The gears 116 and 117 arearranged below the gears III and 107.

Each sensing element 49, 51 is adapted to cooperate through its pin 56or 57 with a tongue 118 or 119 respecti ely ofthe corresponding latchlever 121 or 122 (FIG. I both levers 121 and 122 being fuIcrumed on apin 123 fixed on the base 43. A coil spring 124, fitted over the pin123, has its ends bearing against the tongues 118 and 119 so as tothrust the lever 122 in the clockwise direction and the lever 121 in theanticlockwise direction about the pin 123. Under the action of the coilspring 124, each tongue 118, 119 will be arrested either on a frontshoulder 128 or 129 respectively or on a rear shoulder 120 or 125respectively of a reversal member 131.

The reversal member 131 is constituted by a rocker fulcrumed on a pin132 fixed on the base 43. The rocker 131 can move from a first positionshown in FIG. 7 to a second position shown in FIG. 8 and vice versa,under the action of a coiled expansion spring 133. The rocker 131 (FIG.7) has two lugs 134 and 136 on each of which there is loosely revolvinga pinion 137 or 138 respectively. Each pinion 137, 138 is capable ofengaging selectively with the gear 111 (FIG. 6) or with the gear 107, inorder to connect the gear 111 with the gear 116 and the gear 107 withthe gear 117.

The rocker 131 is provided with two arms 139 (FIG. 7) and 141, each ofwhich has a tongue 142 and 143 respectively. Each tongue 142, 143 cancooperate with a cam part 144 or 146 respectively ofa reload element147.

The reload element 147 is constituted by a sliding plate having agenerally rectangular shape and which rests on the bottom of the base43. The reload element 147 has two windows 148 and 149 in which thereare formed rack teeth 151 or 152 respectively arranged in the samehorizontal plane. The teeth 151, 152 can en gage with a pinion 153 or154 respectively which is in one piece with the shaft 41 or 42respectively and hence with the gear 116 or 117 respectively.

The coiled expansion spring 133 is connected at one end to the rocker131 and at the other end to the reload element 147. In the firstposition of the rocker 131 and of the reload element 147 of FIG. 7, thetongue 118 of the lever 121 is stopped against the front shoulder 128,whilst the tongue 119 of the lever 122 is stopped against the rearshoulder 125 of the rocker 13]. The tension of the coiled expansionspring 133 is such as to keep the rocker 131 stopped with a lateralshoulder 127 against the tongue 119. The reload element 147 is, in itsturn, urged by the coiled expansion spring 133 against two stops 156 and157 of the base 43 and with the pinion 153 adjacent to but disengagedfrom the teeth 151. In the second position of the rocker 131 and of thereload element 147 of FIG. 8, the tongue 118 of the lever 121 is stoppedagainst the rear shoulder and the tongue 119 is stopped against thefront shoulder 129. The tension of the coiled expansion spring 133 keepsthe rocker 131 stopped with a lateral shoulder 126 stopped against thetongue 118. The reload element 147 is, in its turn, stopped against twofixed stops 158 and 159 of the base 43 and with the pinion 154 adjacentto but disengaged from the teeth 152.

In operation it will be assumed that the rocker 131 and the reloadelement 147 are in the first position as shown in FIGS. 5, 6 and 7, inwhich the pinion I37 meshes with the gears I11 and 116. The gear trainfrom 104 to 111 then causes the ribbon 12 to wind on to the spool 18,whereby the ribbon l2 shifts from the right to the left in FIGS. Thelever 52 withdraws the pin 56 from the tongue 118 against the action ofthe spring 54. On the contrary, the pin 57 of the lever 53 approachesthe tongue 119 under the action of the spring 54. The inked ribbon 12continuing to unwind from the spool 19, the lever 53 progressivelyapproaches towards the center of the spool 19 whereby the pin 57 engagesthe tongue 119 and begins to cause the lever 122 (FIG. 7) to rotate inthe anticlockwise direction against the action of the coil spring 124,over which the spring 54 (FIG, 5) prevails. When the coils of inkedribbon 12 wound on the spool 19 are less than a prefixed quantity, thetongue 119 disengages from the lateral shoulder 127 (FIG. 7), wherebythe coiled expansion spring 133 causes the rocker 131 to rotate rapidlyin the anticlockwise direction. The rocker 131 passes from the first position to the second one, placing itself in the position shown by brokenlines in FIG. 7. The tongue 118 in its turn, under the action of thecoil spring 124, then stops on the rear shoulder 120, whilst the tongue119 remains rested against the pin 57, until the coils of inked ribbon12 (FIG. 5) increase on the spool 19, whereby the lever 53 draws awayradially and therefore the tongue 119 engages the front shoulder 129(FIG. 8). The pinion 137 ceases to engage the gears 111 (FIG. 5) and116, thereby stopping temporarily the shaft 41. The pinion 138 thenmeshes with the gears 107 and 117, whereby the shaft 42 can rotate.

At the same time the tongue 143 (FIG. 7) ceases its engagement with thecam part 146 and the tongue 142 engages with the cam part 144. Thecoiled expansion spring 133 assumes a second position shown in brokenlines, causing the reload element 147 to shift backwards until thislatter is stopped against the fixed stop 158 as shown in broken lines inFIG. 7. The teeth I52 therefore come into mesh with the pinion 154.

Because of the rotation of the gears from 104 to 107 (FIG. the pinion138 transmits the movement to the gear 117, and thence to the shaft 42,whereby the inked ribbon 12 starts to wind on to the spool 19. At thesame time the pinion 154 (FIG. 7). which is rotating in theanticlockwise direction, meshes with the teeth 152 and shifts the reloadelement 147 towards the right until it stops against the fixed stop 159.During this displacement. the tongue 142, through the cam part 144.shifts the left hand end of the reload element 147 forwards, so as toprevent the teeth 151 from encountering the teeth of the pinion 153.With this displacement, the various elements assume the stableconfiguration of FIG. 8 already described, whereby the coiled expansionspring 133 now tends to urge the rocker 131 back from the position ofFIG. 8 to that of FIG. 7.

The inked ribbon 12 (FIG. 5) continues to wind on to the spool 19,whereby the lever 53 moves radially against the action of the spring 54.drawing away from the center of the spool 19 and drawing the pin 57 awayfrom the tongue 119. The lever 52 moves on the con trary radially underthe action of the spring 54 towards the center of the spool 18 and movesthe pin 56 towards the tongue 118. Eventually the pin 56 engages thetongue 118. causing the lever 121 (FIG. 8) to rotate in the clockwisedirection against the action of the coil spring 124 until the tongue 118ceases to engage the lateral shoulder 126. The coiled expansion spring133 then causes the rocker 131 to rotate rapidly in the clockwisedirection. thereby to pass from the second position to the firstposition as shown by broken lines in the FIG. 8. The coiled expansionspring 133 assumes the position shown in broken lines in FIG. 8.

The pinion 138 disengages from the gears 107 and 117 (FIG. 5). wherebythe shaft 42 ceases to rotate, and the pinion 137 meshes with the gears111 and 116. The tongue 142 (FIG. 8) disengages from the cam part 144whilst the tongue 143 engages the cam part 146. The coiled expansionspring 133 shifts the reload ele ment 147 backwards untii it stopsagainst the stop 156 as shown by broken lines in FIG. 8. The teeth 151mesh with the pinion 153. The tongue 119, under the action of the coilspring 124, engages with the rear shoulder 125, whilst the tongue 118remains rested against the pin 56, until the coils of inked ribbon 12(FIG. 5) wound on the spool 18 increase, when the lever 52 withdrawsradially and hence the tongue 118 engages the front shoulder 128 (FIG.8).

Through the rotation of the gears from 104 (FIG. 5) to 111, the pinion137 transmits the movement to the gear 116 and hence to the shaft 41whereby the inked ribbon 12 resumes its winding on the spool 18. At thesame time the pinion 153 (FIG. 8), by rotating in the clockwisedirection, meshes with the teeth and shifts the reload element 147 untilit stops against the fixed stop 157. During this displacement the tongue143, engaging the cam part 146. moves the right hand end of the reloadelement 147 forwards so that the teeth 152 do not encounter the teeth ofthe pinion 154. The various elements therefore resume the stable configuration of FIG. 7.

We claim:

1. A removable cartridge for an inked ribbon for an office printingmachine of the type including a supporting platform. two motive shaftsrotatably projecting from said platform. a ribbon reversal feedmechanism including two sensing elements for rotating one or another ofsaid two motive shafts in one predetermined sense of rotation, a closureplate including a central tongue. an engaging tongue projecting fromsaid platform, said closure plate being fulcrumed on said platformbetween an inoperative location and an operative location for causingsaid central tongue to engage said engaging tongue in correspondancewith said operative location of said closure plate. and means connectingsaid closure plate with said two sensing elements for moving saidsensing elements from inoperative positions away from said motive shaftsin correspondence with said inoperative location of said closure plateof operative positions of said sensing elements near said motive shafts,in correspondence with said operative location of said closure plate.said cartridge comprising a. a container including a main wall. a seriesof side elements connected to said main wall perpendicular to said mainwall, two ribbon spools, means rotatably supporting said spools inlateral spaced relation within said container about an axisperpendicular to said main wall. means for accomodating said motiveshafts concentrically with said spools. and an inked ribbon having endsfixed to said spools and wound in coils on said spools. one of said sideelements defining a pair of slits for the passage of said inked ribbonfrom the one to the other of said spools outside said container, andsaid spools being provided with corresponding engaging means forengaging said motive shafts;

b. aperture means on said container for causing said sensing elementsduring the movement thereof from said inoperative positions to saidoperative positions to bear against said coils of ribbons wound on saidspools, and sense the amount of coils of ribbon wound on said spools;and

c. first means defining a recess between said two spools in said mainwall for cooperating with said tongue of said closure plate incorrespondence with the operative location of said closure plate forfixing said container on said platform jointly to the bearing of saidsensing elements against said coils.

2. In an inked ribbon cartridge including a parallelepipedal containerhaving top and bottom walls interconnected by side walls, a pair ofribbon spools variably winding coils of inked ribbon thereon. saidspools being in lateral spaced relation within said container, and meansincluded in said container for rotatably supporting said spools aboutaxes perpendicular to said top and bottom walls, one rear wall of saidside walls including a pair of slots for the passage of a portion ofsaid ribbon from the one to another of said spools outside container.and said bottom wall having a pair of openings therethroughconcentrically aligned with said ribbon spools for causing a pair ofspindle means of a printing calculating machine to engage said pair ofspools. the combination comprising a. a pair of arm members projectingfrom said rear wall adjacent to said pair of slots for guiding saidportion of ribbon parallel to said rear wall a predetermined distancefrom said rear wall along a line of said printing calculating machine.said spindle means being supported by a platform fixed to said printingcalculating machine, and said arm members and said ribbon defining aspace accomodat ing a printing head of said calculating machine incorrespondence with movement of said printing head along said printingline:

b. means defining apertures in a front wall of said side walls oppositeto said rear wall for freely receiving two sensing levers of a ribbonreversal feed mechanism pivoted on said platform of said printingcalculating machine, said two spools being accessible by said sensinglevers through said apertures to be sensed for a predetermined amount ofcoil wound thereon to cause said feed mechanism to drive said pair ofspindles in one sense and the other sense respectively in dependence onsaid amount:

c. a pair of covering portions disposed above said spools and includedin said top wall for covering said pair of spools; and

d. means defining a supporting surface in said container adjacent tosaid pair of covering portions and recessed therein for cooperating witha tongue of a closure member pivotally supported by said platform forpreventing undesired movement of said container and said ribbon jointlywith the sensing of said coils by said sensing levers.

3. A removable cartridge for an inked ribbon ofa calculating machine ofthe type including a supporting platen. a printing head movabletransversely of said platen. a supporting platform transverselystationary with respect to said platen. two motive shafts projectingfrom said platform and rotatably supported therefrom, a ribbon reversalfeed mechanism. two sensing levers fulcrumed on said platform andoperatively connected to said feed mechanism for rotating one or anotherof said two motive shafts in ime predetermined sense of rotation. aclosure plate iggluding a central tongue having a detent lug. anengaging tongue having a shoulder a projecting from sai platform, saidclosure plate being fulcrumed on sai jplatform between an inoperativeand an operative tion, resilient means for causing said dentent lug i ff'said central tongue to engage said shoulder of said eng iging tongue incorresponding with said operative loca 'n of said closure plate andmeans connecting said c it re plate with said two sensing levers forposition said sensing levers from inoperative positions away from saidmotive shafts in correspondence with said inoperative location of saidclosure plate to operative positions of said sensing levers near said.motive shafts in correspondence with said operative location of saidclosure plate, said cartridge comprising:

a. a container including a main wall, a series of side walls connectedto said main wall perpendicular to said main wall, two ribbon spools,means rotatably supporting said spools in lateral spaced relation withinsaid container about axes perpendicular to said main wall, and an inkedribbon having ends fixed to said spools and wound in coils in saidspools, one side wall of said side walls defining a pair of slits forthe passage of a portion of said inked ribbon from the one to the otherof said spools outside said container. and said spools being providedwith corresponding engaging means for engaging said motive shafts;

b. a pair of arm members projecting from said one side wall for guidingsaid portion of inked ribbon parallel to said platen and accomodatingsaid printing head along the transverse movement thereof;

c. aperture means in said container for causing said sensing levers insaid operative positions to be rotated in response to the amount ofcoils of inked ribbon wound on said spools;

d. first means defining a recess in said main wall between said axes forcooperating with said central tongue, in correspondence of the operativeloca tion of said closure plate, and fixing said container on saidplatform; and

e. second means defining a space in said one side wall adjacent saidrecess for accomodating said engaging tongue and said detent lug of saidcentral tongue in the operative location of said closure member,aligning said dentent lug with said one side wall.

4. A removable cartridge for an inked ribbon for an office machine,comprising a container and two ribboncarrying spools rotatable thereinin either direction of rotation, said container having at least a mainwall to which the axes of said spools are perpendicular. a series ofside walls perpendicular to said main wall, a pair of slits in one ofsaid side walls for the passage of the ribbon from the one to the otherof said spools along a path which, between the slits, lies outside saidcontainer, wherein said machine is of the type including two spindlesfor engaging said spools, two sensing elements pivoted on said machine,parallel to said axes for sensing the amount of ribbon carried by saidspools, a feed reversal mechanism connected to said sensing elements fordriving said two spindles in response to the position of said sensingelements, and means for attaching said cartridge to the machine, whereinthe improvement comprises: a pair of apertures in a side wall oppositesaid one side wall, each of said apertures being as sociated with one ofsaid spools, said sensing elements entering said container thru saidapertures to sense said amount of ribbon on said spools, and saidattaching means comprising a closure member, pivot means supporting saidclosure member on the machine for movement between a first position inwhich said closure member holds said cartridge fixed on the machine anda second position in which said cartridge is free to be taken off saidmachine, and a coupling mechanism arranged on said closure member inorder to act on said sensing elements for withdrawing said sensingelements from said apertures when said closure member is in said secondposition.

5. A removable cartridge according to claim 4, wherein said sensingelements comprise a pair of scissor levers mounted on a pivot on themachine and biased by a spring to rotate in opposite senses, therebyentering the two apertures respectively, said coupling mechanism actingon said levers to rotate said levers against the action of the spring,and said cartridge container having a recess in said opposite wallaccommodating said pivot.

6. A removable cartridge according to claim 5, wherein said closuremember comprises a tongue, said tongue, in said first position of saidclosure member, being received within a recess of said main wall of saidcartridge container and being swung away from said main wall recess onmovement to said second position of said closure member.

7. A removable cartridge according to claim 6, wherein the free end ofsaid tongue remote from said pivot means of said closure member ends ina V-shaped projection. said projection carrying a detent lug for engaging a shoulder fixed to the machine, thereby holding said closuremember releasably in the first position, and said cartridge wall isrecessed to accomodate said projection and shoulder.

8. A removable cartridge according to claim 7 to said ribbon slits toguide said ribbon outside said container over a path spaced from saidone side wall, said two arms projecting from said one side wall fordefining a space between said ribbon and said one side wall, withinwhich a printing head of the machine is mov able. said Vshapedprojection and said shoulder being outside the path of movement of saidprinting head.

9. A inked ribbon feed mechansim for an office ma chine comprising:

a. a cartridge including a container. two spools rotat able in saidcontainer, and inked ribbon having one end attached to one of said twospools and the other end attached to the other of said two spools, saidribbon being wound in coils over said spools, two slits in saidcontainer for the passage of said inked ribbon from the one to the otherof said two spools outside said container and means defining a passagein said container;

b. supporting means for removably supporting said container on saidoffice machine;

c, two spindle means rotatable on said supporting means about parallelaxes and engageable by said two spools for respectively rotating saidspools in either direction of rotation:

d. two sensing elements movably supported by said supporting meansbetween an inoperative position away from said spools and an operativeposition wherein said sensing elements bear against said coils of ribbonwound on said spools;

e. a ribbon reversal mechanism operatively connected with said sensingelements when in said operative position for driving one of said twospindle means in a predetermined sense of rotation upon sensing apredetermined amount of said coils being wound on one of said spools;

f, a closure member movably supported by said supporting means between afirst position wherein said closure member fixes said container oversaid supporting means and a second position wherein said closure memberreleases said container for allowing said container to be taken off saidsupporting means along a direction parallel to said axis, said passagedefining means of said cartridge lying in a path outside said sensingelements positioned in said inoperative position; and

g. a coupling mechanism connecting said closure member with said twosensing elements for causing said sensing elements to be positioned insaid inoperative position when said closure member is in said secondposition, so that said container can be freely taken off.

10. An inked ribbon feed mechanism according to claim 9 wherein saidcontainer includes a main wall rotatably supporting said two spoolsabout axes perpendicular to said main wall, a series of side wallsperpendicular to said main wall, said two slits being included in saidside walls and said two sensing elements being in said inoperativeposition away from said container 11. An inked ribbon feed mechanismaccording to claim 9, wherein said supporting means comprise a platformof said machine and said two sensing elements comprise a pair of scissorlevers mounted on a pivot fixed to said platform, said pair of scissorlevers being biased by a spring to rotate in opposite senses toward saidtwo spools when in said operative positions; and said coupling mechanismacting on said pair of scissor levers to rotate said pair of scissorlevers against the ac tion of said spring in said second position ofsaid closure member.

12. An inked ribbon feed mechanism according to claim 9, wherein saidclosure member includes a T shaped plate having two arms and a centraltongue and wherein said supporting means comprise a platform, pivotmeans of said platform pivotally mounting said two arms of said T shapedplate. and a shoulder pro jecting from said platform, one end of saidcentral tongue of said T shaped plate including a V shaped pro jectionand said projection carrying a detent lug for engaging said shoulder inthe first position of said closure member, and fixing said containerover said platform,

13. An inked ribbon feed mechanism according to claim 9. wherein saidribbon reversal mechanism comprises a reversal member engaging, betweena first position and a second position. a corresponding drive element ofa ribbon drive mechanism in order to effect drive of said ribbon spoolsin one sense and the other sense, respectively, a reversal spring andmeans carrying said reversal spring for causing said reversal spring tobias said reversal member from said first position towards said secondposition and vice-versa a pair of latches for arresting said reversalmember in said first position and in said second position against theaction of said reversal spring, each of said pair of latches cooperatingwith a corresponding one of said two sensing elements in order todisengage said reversal member when the inked ribbon on thecorresponding spool has reached a minimum quantity such as to requirereversal of the inked ribbon, thereby causing said reversal spring tomove said reversal member from said first position to the secondposition and vice-versa and a reload element responsive to the movementof said reversal member for repositioning said carrying means forcausing said reversal spring to bias said reversal member from saidsecond position back towards said first position and vice-versa.

14. An inked ribbon feed mechanism according to claim 13 wherein saidribbon drive mechanism comprises two spool gears coupled to said twospindle means, respectively, and a train of further gears driven by adrive shaft rotatable in a single direction, two oppositely rotatingones of said further gears being parallel to and coaxial with said twospool gears, respectively, and said drive elements including two pinionsfreely rotatable on said reversal member, said reversal member, in saidfirst position and in said second position causing a corresponding oneof said pinions to be meshed with a corresponding one of said spoolgears and with the further gear coaxial with said spool gear.

15. A device for fixing a removable cartridge for inked ribbon to anoffice machine, wherein said cartridge comprises: a container rotatablysupporting two ribbon-carrying spools, a cover of said container towhich the axes of said spools are perpendicular, a series of side wallsperpendicular to said cover, a pair of slits in one of said side wallsfor the passage of the ribbon from the one to the other of said spools,and a pair of apertures in a side wall opposite the said one side wall,each of said apertures being associated with a corresponding one of saidspools, said office machine comprising a reversably feeding ribbonmechanism provided with a pair of sensing elements for sensing the mountof ribbon on said spools, said fixing device comprising a closuremember, a coupling mechanism prise a pair of scissor levers biased by aspring for hearing against said ribbon on said two spools, respectively,said cam means being arranged to transmit thrust to said levers, inorder to rotate said levers against the action of said spring when theclosure member is moved from said first position to said secondposition.

17. A device according to claim 16, wherein said cam means transmitthrust to said levers through two rocking levers pivotally mounted onthe machine.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N 795 DatedJune 17, 1975 Inventor) Sergio Garberi, Lorenzo Bertino It is certifiedthat error appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

The foreign application priority data should read as follows:

October 21, 1971 Italy 70460-A/71 May 3, 1972 Italy 68360-A/72 Signedand Scaled this Twenty-second Day Of February 1977 [SEAL] Arrest:

RUTH C. MASON C. MARSHALL DANN Arresting Office Commissioner nflarentsand Trademarks

1. A removable cartridge for an inked ribbon for an office printingmachine of the type including a supporting platform, two motive shaftsrotatably projecting from said platform, a ribbon reversal feedmechanism including two sensing elements for rotating one or another ofsaid two motive shafts in one predetermined sense of rotation, a closureplate including a central tongue, an engaging tongue projecting fromsaid platform, said closure plate being fulcrumed on said platformbetween an inoperative location and an operative location for causingsaid central tongue to engage said engaging tongue in correspondancewith said operative location of said closure plate, and means connectingsaid closure plate with said two sensing elements for moving saidsensing elements from inoperative positions away from said motive shaftsin correspondence with said inoperative location of said closure plateof operative positions of said sensing elements near said motive shafts,in correspondence with said operative location of said closure plate,said cartridge comprising a. a container including a main wall, a seriesof side elements connected to said main wall perpendicular to said mainwall, two ribbon spools, means rotatably supporting said spools inlateral spaced relation within said container about an axisperpendicular to said main wall, means for accomodating said motiveshafts concentrically with said spools, and an inked ribbon having endsfixed to said spools and wound in coils on said spools, one of said sideelements defining a pair of slits for the passage of said inked ribbonfrom the one to the other of said spools outside said container, andsaid spools being provided with corresponding engaging means forengaging said motive shafts; b. aperture means on said container forcausing said sensing elements during the movement thereof from saidinoperative positions to said operative positions to bear against saidcoils of ribbons wound on said spools, and sense the amount of coils ofribbon wound on said spools; and c. first means defining a recessbetween said two spools in said main wall for cooperating with saidtongue of said closure plate in correspondence with the operativelocation of said closure plate for fixing said Container on saidplatform jointly to the bearing of said sensing elements against saidcoils.
 2. In an inked ribbon cartridge including a parallel-epipedalcontainer having top and bottom walls interconnected by side walls, apair of ribbon spools variably winding coils of inked ribbon thereon,said spools being in lateral spaced relation within said container, andmeans included in said container for rotatably supporting said spoolsabout axes perpendicular to said top and bottom walls, one rear wall ofsaid side walls including a pair of slots for the passage of a portionof said ribbon from the one to another of said spools outside container,and said bottom wall having a pair of openings therethroughconcentrically aligned with said ribbon spools for causing a pair ofspindle means of a printing calculating machine to engage said pair ofspools, the combination comprising a. a pair of arm members projectingfrom said rear wall adjacent to said pair of slots for guiding saidportion of ribbon parallel to said rear wall a predetermined distancefrom said rear wall along a line of said printing calculating machine,said spindle means being supported by a platform fixed to said printingcalculating machine, and said arm members and said ribbon defining aspace accomodating a printing head of said calculating machine incorrespondence with movement of said printing head along said printingline; b. means defining apertures in a front wall of said side wallsopposite to said rear wall for freely receiving two sensing levers of aribbon reversal feed mechanism pivoted on said platform of said printingcalculating machine, said two spools being accessible by said sensinglevers through said apertures to be sensed for a predetermined amount ofcoil wound thereon to cause said feed mechanism to drive said pair ofspindles in one sense and the other sense respectively in dependence onsaid amount; c. a pair of covering portions disposed above said spoolsand included in said top wall for covering said pair of spools; and d.means defining a supporting surface in said container adjacent to saidpair of covering portions and recessed therein for cooperating with atongue of a closure member pivotally supported by said platform forpreventing undesired movement of said container and said ribbon jointlywith the sensing of said coils by said sensing levers.
 3. A removablecartridge for an inked ribbon of a calculating machine of the typeincluding a supporting platen, a printing head movable transversely ofsaid platen, a supporting platform transversely stationary with respectto said platen, two motive shafts projecting from said platform androtatably supported therefrom, a ribbon reversal feed mechanism, twosensing levers fulcrumed on said platform and operatively connected tosaid feed mechanism for rotating one or another of said two motiveshafts in one predetermined sense of rotation, a closure plate includinga central tongue having a detent lug, an engaging tongue having ashoulder a projecting from said platform, said closure plate beingfulcrumed on said platform between an inoperative and an operativelocation, resilient means for causing said dentent lug of said centraltongue to engage said shoulder of said engaging tongue in correspondingwith said operative location of said closure plate and means connectingsaid closure plate with said two sensing levers for position saidsensing levers from inoperative positions away from said motive shaftsin correspondence with said inoperative location of said closure plateto operative positions of said sensing levers near said, motive shaftsin correspondence with said operative location of said closure plate,said cartridge comprising: a. a container including a main wall, aseries of side walls connected to said main wall perpendicular to saidmain wall, two ribbon spools, means rotatably supporting said spools inlateral spaced relation within said container about axes perpendicularto said main wall, and an inked ribbon having ends fixed to said spoolsand wound in coils in said spools, one side wall of said side wallsdefining a pair of slits for the passage of a portion of said inkedribbon from the one to the other of said spools outside said container,and said spools being provided with corresponding engaging means forengaging said motive shafts; b. a pair of arm members projecting fromsaid one side wall for guiding said portion of inked ribbon parallel tosaid platen and accomodating said printing head along the transversemovement thereof; c. aperture means in said container for causing saidsensing levers in said operative positions to be rotated in response tothe amount of coils of inked ribbon wound on said spools; d. first meansdefining a recess in said main wall between said axes for cooperatingwith said central tongue, in correspondence of the operative location ofsaid closure plate, and fixing said container on said platform; and e.second means defining a space in said one side wall adjacent said recessfor accomodating said engaging tongue and said detent lug of saidcentral tongue in the operative location of said closure member,aligning said dentent lug with said one side wall.
 4. A removablecartridge for an inked ribbon for an office machine, comprising acontainer and two ribbon-carrying spools rotatable therein in eitherdirection of rotation, said container having at least a main wall towhich the axes of said spools are perpendicular, a series of side wallsperpendicular to said main wall, a pair of slits in one of said sidewalls for the passage of the ribbon from the one to the other of saidspools along a path which, between the slits, lies outside saidcontainer, wherein said machine is of the type including two spindlesfor engaging said spools, two sensing elements pivoted on said machine,parallel to said axes for sensing the amount of ribbon carried by saidspools, a feed reversal mechanism connected to said sensing elements fordriving said two spindles in response to the position of said sensingelements, and means for attaching said cartridge to the machine, whereinthe improvement comprises: a pair of apertures in a side wall oppositesaid one side wall, each of said apertures being associated with one ofsaid spools, said sensing elements entering said container thru saidapertures to sense said amount of ribbon on said spools, and saidattaching means comprising a closure member, pivot means supporting saidclosure member on the machine for movement between a first position inwhich said closure member holds said cartridge fixed on the machine anda second position in which said cartridge is free to be taken off saidmachine, and a coupling mechanism arranged on said closure member inorder to act on said sensing elements for withdrawing said sensingelements from said apertures when said closure member is in said secondposition.
 5. A removable cartridge according to claim 4, wherein saidsensing elements comprise a pair of scissor levers mounted on a pivot onthe machine and biased by a spring to rotate in opposite senses, therebyentering the two apertures respectively, said coupling mechanism actingon said levers to rotate said levers against the action of the spring,and said cartridge container having a recess in said opposite wallaccommodating said pivot.
 6. A removable cartridge according to claim 5,wherein said closure member comprises a tongue, said tongue, in saidfirst position of said closure member, being received within a recess ofsaid main wall of said cartridge container and being swung away fromsaid main wall recess on movement to said second position of saidclosure member.
 7. A removable cartridge according to claim 6, whereinthe free end of said tongue remote from said pivot means of said closuremember ends in a V-shaped projection, said projection carrying a detentlug for engaging a shoulder fixed to the machine, thereby holding saidclosure member releasably in the first position, and said cartridge wallis recessed to accomodate said projection and shoulder.
 8. A removablecartridge according to claim 7 to said ribbon slits to guide said ribbonoutside said container over a path spaced from said one side wall, saidtwo arms projecting from said one side wall for defining a space betweensaid ribbon and said one side wall, within which a printing head of themachine is movable, said V-shaped projection and said shoulder beingoutside the path of movement of said printing head.
 9. A inked ribbonfeed mechansim for an office machine comprising: a. a cartridgeincluding a container, two spools rotatable in said container, and inkedribbon having one end attached to one of said two spools and the otherend attached to the other of said two spools, said ribbon being wound incoils over said spools, two slits in said container for the passage ofsaid inked ribbon from the one to the other of said two spools outsidesaid container and means defining a passage in said container; b.supporting means for removably supporting said container on said officemachine; c. two spindle means rotatable on said supporting means aboutparallel axes and engageable by said two spools for respectivelyrotating said spools in either direction of rotation; d. two sensingelements movably supported by said supporting means between aninoperative position away from said spools and an operative positionwherein said sensing elements bear against said coils of ribbon wound onsaid spools; e. a ribbon reversal mechanism operatively connected withsaid sensing elements when in said operative position for driving one ofsaid two spindle means in a predetermined sense of rotation upon sensinga predetermined amount of said coils being wound on one of said spools;f. a closure member movably supported by said supporting means between afirst position wherein said closure member fixes said container oversaid supporting means and a second position wherein said closure memberreleases said container for allowing said container to be taken off saidsupporting means along a direction parallel to said axis, said passagedefining means of said cartridge lying in a path outside said sensingelements positioned in said inoperative position; and g. a couplingmechanism connecting said closure member with said two sensing elementsfor causing said sensing elements to be positioned in said inoperativeposition when said closure member is in said second position, so thatsaid container can be freely taken off.
 10. An inked ribbon feedmechanism according to claim 9 wherein said container includes a mainwall rotatably supporting said two spools about axes perpendicular tosaid main wall, a series of side walls perpendicular to said main wall,said two slits being included in said side walls and said two sensingelements being in said inoperative position away from said container.11. An inked ribbon feed mechanism according to claim 9, wherein saidsupporting means comprise a platform of said machine and said twosensing elements comprise a pair of scissor levers mounted on a pivotfixed to said platform, said pair of scissor levers being biased by aspring to rotate in opposite senses toward said two spools when in saidoperative positions; and said coupling mechanism acting on said pair ofscissor levers to rotate said pair of scissor levers against the actionof said spring in said second position of said closure member.
 12. Aninked ribbon feed mechanism according to claim 9, wherein said closuremember includes a T shaped plate having two arms and a central tongueand wherein said supporting means comprise a platform, pivot means ofsaid platform pivotally mounting said two arms of said T shaped plate,and a shoulder projecting from said platform, one end of said centraltongue of said T shaped plate including a V shaped projection and saidprojection carrying a detent lug for engaging said sHoulder in the firstposition of said closure member, and fixing said container over saidplatform.
 13. An inked ribbon feed mechanism according to claim 9,wherein said ribbon reversal mechanism comprises a reversal memberengaging, between a first position and a second position, acorresponding drive element of a ribbon drive mechanism in order toeffect drive of said ribbon spools in one sense and the other sense,respectively, a reversal spring and means carrying said reversal springfor causing said reversal spring to bias said reversal member from saidfirst position towards said second position and vice-versa a pair oflatches for arresting said reversal member in said first position and insaid second position against the action of said reversal spring, each ofsaid pair of latches cooperating with a corresponding one of said twosensing elements in order to disengage said reversal member when theinked ribbon on the corresponding spool has reached a minimum quantitysuch as to require reversal of the inked ribbon, thereby causing saidreversal spring to move said reversal member from said first position tothe second position and vice-versa and a reload element responsive tothe movement of said reversal member for repositioning said carryingmeans for causing said reversal spring to bias said reversal member fromsaid second position back towards said first position and vice-versa.14. An inked ribbon feed mechanism according to claim 13 wherein saidribbon drive mechanism comprises two spool gears coupled to said twospindle means, respectively, and a train of further gears driven by adrive shaft rotatable in a single direction, two oppositely rotatingones of said further gears being parallel to and coaxial with said twospool gears, respectively, and said drive elements including two pinionsfreely rotatable on said reversal member, said reversal member, in saidfirst position and in said second position causing a corresponding oneof said pinions to be meshed with a corresponding one of said spoolgears and with the further gear coaxial with said spool gear.
 15. Adevice for fixing a removable cartridge for inked ribbon to an officemachine, wherein said cartridge comprises: a container rotatablysupporting two ribbon-carrying spools, a cover of said container towhich the axes of said spools are perpendicular, a series of side wallsperpendicular to said cover, a pair of slits in one of said side wallsfor the passage of the ribbon from the one to the other of said spools,and a pair of apertures in a side wall opposite the said one side wall,each of said apertures being associated with a corresponding one of saidspools, said office machine comprising a reversably feeding ribbonmechanism provided with a pair of sensing elements for sensing the mountof ribbon on said spools, said fixing device comprising a closuremember, a coupling mechanism mounted on said closure member cooperatingwith said sensing elements, and pivot means of said machine pivotallymounting said closure member for movement between a first positionwherein said closure member cooperates with said cover for holding saidcartridge fixed to said machine and a second position wherein saidcoupling mechanism withdraws said sensing elements from said apertures.16. A device according to claim 15, wherein said coupling mechanismcomprises: cam means on the closure member and wherein said sensingelements comprise a pair of scissor levers biased by a spring forbearing against said ribbon on said two spools, respectively, said cammeans being arranged to transmit thrust to said levers, in order torotate said levers against the action of said spring when the closuremember is moved from said first position to said second position.
 17. Adevice according to claim 16, wherein said cam means transmit thrust tosaid levers through two rocking levers pivotally mounted on the machine.